This invention relates to an optical recording medium having recorded thereon second data, as supplementary data, in addition to first data as main data, a recording method and apparatus for recording the supplementary data along with the main data on this optical recording medium and a method and apparatus for reproducing an optical recording medium having the first and second data recorded thereon.
More particularly, this invention relates to an optical recording medium in which the shape of plural pits of a track comprised of the pits representing recording data and lands between these pits is deformed to record other data, a recording method and apparatus for recording data on the optical recording medium and to a method and apparatus for reproducing the optical recording medium.
Up to now, an optical disc, such as a compact disc with a diameter equal to 12 cm, is widely employed as an optical recording medium having recorded thereon audio data, such as music numbers.
In recording on this optical disc, audio data is sequentially blocked and added to with an error correction code. The resulting data is modulated with EFM (eight to fourteen modulation), with the results of the modulation being recorded by NRZI (non-return-to-zero inverted) modulation. On the compact disc, audio data is recorded by repetition of pits and lands with nine different lengths of the periods of 3T to 11T, where T is the basic period equal to the channel clock period.
The pits formed in the optical disc based on the recorded audio data are of length in the track direction equal to approximately 0.87 to 3.18 xcexcm, in association with the periods of 3T to 11T, with the pit width corresponding to the length in a direction perpendicular to the track direction being approximately 0.5 xcexcm, with its depth being approximately 0.1 xcexcm.
Meanwhile, in a compact disc, audio data is recorded in a frequency range of 20 Hz to 20 kHz. However, a demand is raised to enable audio data to be recorded over a broader frequency range to realize audio reproduction of a higher sound quality. There is also raised a demand for recording audio data of three or more channels, instead of two channels, that is left and right channels, to enable variegated audio reproduction, such as surround reproduction.
Moreover, there is raised a demand for enabling audio data recorded on an optical disc to be reproduced only under a pre-set condition to protect the recorded audio data.
It is an object of the present invention to provide an optical recording medium enabling variegated audio reproduction by recording supplementary data in addition to main data, a method and apparatus for recording data on this optical recording medium and a method and apparatus for reproducing the optical recording medium.
It is another object of the present invention to provide an optical recording medium which enables at least main data to be reproduced using a customary optical disc player and on which has been recorded supplementary data in addition to the main data, and a method and apparatus for recording data on this optical recording medium.
It is still another object of the present invention to provide an optical recording medium which enables recording of audio data of a frequency range broader than that of the customary compact disc or multi-channel audio reproduction to a high sound quality, and a method and apparatus for recording data on this optical recording medium.
It is yet another object of the present invention to provide an optical recording medium which enables reliable protection of recorded data and a method and apparatus for recording data on this optical recording medium.
For accomplishing the above object, the present invention provides an optical recording medium including a track constituted by a plurality of pits formed based on first data recorded therein and lands defined between the pits, wherein the plural pits are deformed based on second data.
The present invention also provides a recording apparatus for an optical recording medium including an objective lens for converging a recording laser beam outputted by a modulator for modulating the recording laser beam radiated by a light source for radiating the recording laser beam based on the furnished first data and second data to the optical recording medium. This recording apparatus includes a signal processor for generating first data based on main data recorded on the optical recording medium and for generating second data based on supplementary data of the main data recorded on the optical recording medium.
The present invention also provides a reproducing apparatus for an optical recording medium, the apparatus including an optical pickup for reading out first and second data from an optical recording medium including a track formed by a plurality of pits formed based on the first data recorded therein and a land defined between neighboring pits, with the pits being deformed based on the second data, a first demodulator for demodulating the first data of the optical recording medium based on an output signal of the optical pickup, and a second demodulator for demodulating the second data of the optical recording medium based on the output signal of the optical pickup. The second demodulator includes a demodulation processor for demodulating an output of the signal level discriminating portion adapted for discriminating the signal level of the playback signal supplied from the signal processor.
Preferably, the reproducing apparatus also includes a synthesizing portion for synthesizing an output signal of the first demodulator and an output signal of the second demodulator. The reproducing apparatus also includes an external equipment discriminating portion for discriminating whether or not an external equipment connected to the apparatus is an authentic external equipment. Tile reproducing apparatus outputs at least an output signal of the second modulator when the an external equipment connected to the apparatus is discriminated by the external equipment discriminating portion to be an authentic external equipment.
The optical pickup preferably includes a photodetector split in the track direction of the optical recording medium at least into a first photodetector portion and a second photodetector portion. The apparatus also includes a signal processor for processing output signals of the first and second photodetector portions. The first demodulator is fed from the signal processor with a sum signal representing the sum of output signals of the first and second photodetector portions, whilst the second demodulator is fed from the signal processor with a difference signal representing the difference between output signals of the first and second photodetector portions.
The present invention also provides a reproducing apparatus for an optical recording medium including an optical pickup for reading out first and second data and discriminating data from an optical recording medium including a track formed by a plurality of pits formed based on the first data recorded therein and a land defined between neighboring pits, with the pits being deformed based on the second data. The optical recording medium also has the discriminating data recorded thereon. The reproducing apparatus for an optical recording medium also includes a first demodulator for demodulating the first data of the optical recording medium based on an output signal of the optical pickup, a second demodulator for demodulating the second data of the optical recording medium based on the output signal of the optical pickup and a controller for controlling the operation of the second demodulator based on the discriminating data read out by the optical pickup from the optical recording medium.
The present invention also provides an optical recording medium including a data recording area having a spirally extending track constituted by a plurality of pits formed based on first data recorded therein and lands defined between neighboring pits, and a management data area for recording therein management data for the first data recorded in the data recording area. At least the plural bits recorded in the management area are previously deformed based on the second data.
Preferably, the first data is digital data recorded on the optical recording medium, whilst the second data is supplementary data to the digital data. The supplementary data is data at least including copyright data.
Preferably, the first data is upper bits of digital data recorded on the optical recording medium, whilst the second data is lower bits of the digital data.
In the management data area, there is preferably recorded discriminating data indicating whether or not the second data is recorded on the optical recording medium.
Preferably, the first data recorded on the optical recording medium is encrypted, whilst the second data is recorded as key data for decrypting the first data.
The present invention also provides a method for recording an optical recording medium including modulating a recording laser beam outputted by a light source with furnished first and second data, converging the modulated recording laser beam on an optical recording medium through an objective lens for forming a track including at least a plurality of pits derived from the first data and lands defined between the pits and deforming the pits formed on the optical recording medium based on the second data. The first data is generated based on the main data recorded on the optical recording medium, whilst the second data is generated based on the supplementary data to the main data recorded on the optical recording medium.
The present invention also provides a method for reproducing an optical recording medium including reading out first and second data from an optical recording medium including a track formed by a plurality of pits formed based on the first data recorded therein and a land defined between neighboring pits, the pits being deformed based on the second data, demodulating the first data of the optical recording medium based on an output signal of data read out from the optical recording medium and demodulating the second data based on playback signals of data read out from the optical recording medium.
Preferably, the signal level of the playback signals read out from the optical recording medium is discriminated to demodulate the second data.
Preferably, the demodulated first and second data are synthesized together and outputted.
In this reproducing method, at least demodulated second data preferably is outputted and reproduced when an external equipment connected to a reproducing apparatus is discriminated to be an authentic external equipment.
The present invention also provides a reproducing method for an optical recording medium including demodulating first data based on playback signals of data read out from an optical recording medium including a track made up of a plurality of pits formed based on the first data recorded and lands defined between neighboring pits, with the plural bits being deformed based on second data, with the optical recording medium having discriminating data recorded thereon, and demodulating the second data based on playback signals of data read out from the optical recording medium based on the results of discrimination of the discrimination data read out from the optical recording medium. If the discriminating data recorded on the optical recording medium indicates that the second data has been recorded on the optical recording medium, the second data is demodulated based on the data read out from the optical recording medium.
Other objects and advantages of the present invention will become apparent from the following description which is ma de with reference to the accompanying drawings.